Anchors ^, ^^, $, $$, «, » confused in <?after>

[p6rt]

Migrated from rt.perl.org#131964 (status was 'resolved')

Searchable as RT131964$

[p6rt]

From xiaowei.lxw@alibaba-inc.com

$ perl6 -e 'say "foo".subst(/<?after ^>/, "^").subst(/<?after $>/, "\$")'$foo^ # should be ^foo$

[p6rt]

From @moritz

This is Rakudo version 2017.08-11-g6cec6b7 built on MoarVM version
2017.08.1-19-g151a256
implementing Perl 6.c.

Rakudo confuses <?after ^> with <?after $> in a regex, and the same with
^^ and $$.

The following four test cases should all pass (barring a thinko on my
part), but instead they all fail​:

#!/usr/bin/env perl6
use Test;

given "abc\ndef" {
  is S/ <?after ^> /X/, "Xabc\ndef", '^ in <?after>';
  is S/ <?after $&gt; /X/, "abc\ndefX", '$ in <?after>';
  is S​:g/ <?after ^^> /X/, "Xabc\nXdef", '^^ in <?after>';
  is S​:g/ <?after $$> /X/, "abcX\ndefX", '^^ in <?after>';
}
done-testing

Kudos go to _cronus on #perl6 for asking about a weird behavior, which
led to the discovery of this bug.

Cheers,
Moritz

Moritz Lenz
Design & Architecture (CDA)
noris network
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Deutschland
Tel +49 911 9352 1517
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[p6rt]

From @moritz

Oh, I forgot to add​: it's not specific to S/// or any kind of substitution; the same problem is in normal regex matches; the substitution is just there to illustrate the point a bit better.

[p6rt]

From @moritz

Tests added to S05-metasyntax/lookaround.t in this commit​: Raku/roast@1089a7f9b7

[p6rt]

From @zoffixznet

IRC​: https://irclog.perlgeek.de/perl6/2017-09-01#i_15101726

If `^` or `«` is used in `<after>` the match fails​:

15​:13 ab6tract m​: say "What​::Root​::Thing" ~~ /<?after ^ "What​::Root​::"> .*/; say "What​::Root​::Thing" ~~ /<?after "What​::Root​::"> .*/
15​:13 camelia rakudo-moar 909688​: OUTPUT​: «Nil??Thing??»

15​:23 m​: say ".zXXXYzYYY" ~~ /<?after « z> .../
15​:23 camelia rakudo-moar 909688​: OUTPUT​: «Nil?»

Even though, `<|w>` and `<!|w>` in `<after>` as well as `$` in `<before>` do work​:

15​:23 m​: say ".zXXXYzYYY" ~~ /<?after <|w> z> .../
15​:23 camelia rakudo-moar 909688​: OUTPUT​: «?XXX??»
15​:23 Zoffix m​: say ".zXXXYzYYY" ~~ /<?after <!|w> z> .../
15​:23 camelia rakudo-moar 909688​: OUTPUT​: «?YYY??»

15​:17 m​: say "XXXzYYYz" ~~ /... <before z> /
15​:17 camelia rakudo-moar 909688​: OUTPUT​: «?XXX?? before => ???»
15​:17 Zoffix m​: say "XXXzYYYz" ~~ /... <before z$> /
15​:17 camelia rakudo-moar 909688​: OUTPUT​: «?YYY?? before => ???»

[p6rt]

From @smls

Duplicate of https://rt-archive.perl.org/perl6/Ticket/Display.html?id=131964 ?

[p6rt]

The RT System itself - Status changed from 'new' to 'open'

[p6rt]

From @usev6

This has been fixed with Raku/nqp@075ff765f5

The tests in S05-metasyntax/lookaround.t are passing, so I'm closing this ticket was 'resolved'.

[p6rt]

From @usev6

This has been fixed with Raku/nqp@075ff765f5

The tests in S05-metasyntax/lookaround.t are passing, so I'm closing this ticket was 'resolved'.

[p6rt]

@usev6 - Status changed from 'new' to 'resolved'